A PRELIMINARY STUDY ON DETECTION OF CADMIUM (II) ION USING BENZOYL PHENYLTHIOUREA

Two benzoyl phenylthiourea derivatives namely: 1-benzoyl-3-(4-bromophenyl)-2- thiourea (M) and 1-(4-chlorobenzoyl)-3-(4-methylphenyl)-2-thiourea (MI) were successfully synthesized and characterized by using Carbon, Hydrogen and Nitrogen (CHN) micro elemental analysis, Fourier Transform Infra-Red (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy methods. Elemental analysis for M (C14H11N2SOBr) and MI (C15H13N2SOCl) were compatible with the expected theoretical calculation. The FTIR spectrum obtained for M and MI compounds show the presence of four important functional groups; ʋ(N-H), ʋ(C=O), ʋ(C-N) and ʋ(C=S) that appeared at 3380-3367 cm-1, 1666-1681 cm-1, 1342-1268 cm-1 and 1146-1152 cm-1, respectively. The NMR spectrum data for MI shows the chemical shift at 6.63-7.85 ppm for Ar-H group, 2.26-2.40 ppm for methyl group, 7.44 ppm for N1H and 3.09 ppm for N2H. For the application, M and MI were used as probes in detecting Cd2+ in methanol solution. UV-Visible spectrophotometer was used to analyze the absorbance values of the compound before and after Cd2+ was added. It is found that compound M displayed the behavior of ‘turn off’ sensors while compound MI possessed the behavior of ‘turn on’ when detecting 0.5×10-5 M and 1×10- 5 M of Cd2+ ion. The behavior of ‘turn on’ and ‘turn off’ is due to the increasing or decreasing of absorbance when Cd2+ was added to the compounds.